Telescoping mast



Feb. 10, 1959 J. H. VAN DEN BEEMT 2,872,904

TELESCOPING MAST Filed May 18. 1953 2 Sheets-Sheet 1 FIG. 1B.

INVENTOR. JAN H. VAN DEN BEEMT 50- 4O 3O 20 I0 ATTORNEYS Feb. 10, 1959 J. H. VAN DEN BEEMT 2,872,904

' TELESCdPING MAST Filed May 18. 1953 2 Sheets-Sheet 2 INVENTOR. JAN H. VAN DEN BEEMT ATTORNEYS FIG. 2.

United States 2,872,904 Patented Feb. 10, 1959 1,872,904 'llIELESCORING MAST JanH. Van den Beemt, Jarrettown, Pa. Application May 18, 1953, s erialvNo. 355,612 12 Claims. ((1121-46) This invention relates to a telescoping mast and, more particularly, to a type of collapsible mast tower which may be adapted, for example, for use as a television antenna mast tower.

In those areas of the country which are relatively remote from television transmitting stations it is necessary, in order to provide satisfactory television reception, that the antenna be raiseda considerable distance above the surface of the earth. In those regions, for example, such as Florida in which high velocity winds occur with some frequency, it is desirable that apparatus such as a high mast tower be of such a nature that it can be taken down or collapsed in order to prevent damage thereto or destruction thereof by such winds. A similar requirement may occur in conjunction with other mast tower applications.

it is an object of this invention to provide an apparatus forming a mast tower which may be rapidlyand easily collapsed or extended when necessary.

A domestic water supply provides a generallyalways available convenient source of power and a convenient means by which a collapsible mast tower may be extended. The limitation to this source of power is, how ever, the fact that the domestic water pressure generally available is insufiicient to lift a column of water the entire height to which it is desired to raise even 'a moderately high mast tower.

it is, therefore, an object of this invention to provide a collapsible mast tower which can be extended by the use of water pressure and which will, by its operation,

raise its uppermost section or sections above the maximum elevation above the surface of the earth attainable by a column of water driven upwardly by the available water pressure.

It is a further object of this invention to provide a telescoping mast tower which may be extended merely by the admission of an operating fluid thereto and which may be collapsed by manual operation of a single release mechanism in conjunction with the manipulation of a valve or valves to provide suitable cushioning for the mast tower sections as they collapse.

These and other objects of the invention will become apparent from the following description when read in conjunction with the accompanying drawings in which:

Figure 1A is a vertical section through the lower portion of a collapsed mast tower;

Figure 1B isa vertical section through the upper portion of a collapsed mast tower;

Figure 2 is a vertical section through portions of the mast tower in an extended condition;

Figure 3 is a plan view of an enlarged showing of a detail of the apparatus shown in Figures 1 and 2;

Figure 4 is a vertical section of an alternate form of the apparatus shown in Figure 3; and

Figure 5 is a vertical sectionof an alternate form of a portion of the apparatus shown in Figures 1 and 2.

Referring to the drawings, the mast tower "includes a plurality of telescoping sections or tubes ll), 20, 30,

40 and 50. While five tubes are shown in the drawings, it will be evident that any number of tubes may be employed within the structural limits of the materials involved. The inner tube 5%, which is the uppermost tube when the mast is extended, is provided at its lower end with a cup or piston member 52 which serves to close oif the lower end of the tube. A sleeve 54 is attached to the exterior of the lower portionof the-tube and extends below the lower portion of the tube 50. Attached to the exteriorof the tube 50 a small distance above the sleeve 54 is a ring-56. Attachedtothe upper end of the tube 50 is a closure cap 58.

The intermediate tubes 20, 30 and 40 are each identical except for diameter and reference to the tube '20 and its associated parts will serve to describe tubes 30 and 4t and their associated parts. A piston 22is fixed to the interior of thelower end of the sleeve 20. A skirt 24 extends downwardly from the lower portion of the sleeve and spaced a slight distance above the skirt is a ring 26 also affixed to the exterior of the tube Edi. Attached to the upper end of the tube 20 and to the exterior thereof is a sleeve 28 having an inwardly turned flange 2% at itsupperrnost end. The space within the inside edge of the .fiange 29 is such as to provide a sliding fit with the next successive tube 30. The flanged sleeves 18, 28, 38 and 48 are each provided with a bore 17, 27, 37 and 47, respectively.

The diameters of the parts are such that the skirt 24 of the tube 20 forms a snug sliding fit with the outermost tube ill. Similarly, the ring 26 positioned immediately above the skirt 24 also provides a snug sliding fit with the .outermost tube 10. The skirt 34 of the tube 30 provides a sliding -fit within the tube 20 and the skirt 34 of the tube provides a sliding fit within the tube 30 and the skirt 54 of the'tube provides a sliding fit within the tube .40.

Thetube 10 is provided at its upper end with a-sleeve 18 having an inwardly turned upper flange 19 which is in sliding engagement with the tube 20. A closure plate 12 is mounted in the lower end of the tube 10 and is adapted to seal otf the'lower end thereof. A ring 16;is attached to the lower portion of the tube 10 and spaced sufficiently far above the lower end thereof to provide sufiicient hearing area between the lower portion of the tube .10 and a tube which provides a mounting for the mast tower. v The tube 60 may be embedded in the ground as indicated at 62 or may be provided with clamping means whereby it may be attached, for example, to the side of a building or to a chimney or other support in a conventional manner.

The tubes, rings, sleeve, skirts and pistons are preferably made of a light, strong and suitable corrosion resistant material such as, for example, one of the numerous well known aluminum alloys and are joined by re sistance welding or other suitable means and the entire assembly is so dimensioned that the successive tubes slide smoothly on their rings and skirts one within the other as described above to provide for extension and collapse or telescoping of themast tower tubes.

A liquid inlet pipe 64 is connected through a conventional valve 66 to a pipe 63 which passes through a slot 61 in the wall of the supporting tube 60 and is turned to extend upwardly through and in sealing engagement with the closure plate 12 in the tube 10. The pipe 68 extends upwardly within the concentrically arranged telescoping tubes and terminates, as indicated at 70, in an upper end which has been rolled inwardly to provide a rounded end surface and yet retain an opening through which fluids maybe discharged. The upper end 70 of the inlet pipe is extended upwardly into the outermost mast tube 10 to a position above the piston of the mast tube 4%} which is the first tube outwardly of the uppermost tube. The uppermost tube has, as previously described, a solid cup or piston 52 secured in its lower end portion which, when the mast is collapsed, comes to rest immediately above the uper end 70 of the inlet pipe. The upper portion of the inlet pipe 68 may be provided with radially extending bores 72 in order to provide additional passage for the flow of liquid outwardly from the pipe and to insure against the possibility of the piston 52 of the uppermost tube squarely sealing off the end of the inlet pipe 68.

The intermediate tubes 20, 30 and 48 are provided with the pistons 22, 32 and 42, respectively, each of which has a central bore 25, 35 and 45, respectively, allowing the inlet pipe 68 to pass therethrough. Mounted on the pistons 22, 32 and 42 are flap valves 23, 33 and 43, respectively. These valves may be made of a flexible material such as rubber and, as shown in detail in Figure 3, are each attached to its associated piston by resistance welding, riveting or bolting through the center of a cup member 73 which is seated in a bore in the valve and has an upper flange 74 which extends over and serves to engage the flap valve and hold it in position upon the piston. A weight 75 may be provided to insure closure of the flap valve or, alternately, a wire spring member may be engaged beneath the rim of the cup 73 and formed so as to urge the flap in a closed position in a conventional fashion. Thus each piston and its associated valve serve as close olf means for its associated tube.

An alternate form of valve is shown in Figure 4. This valve is of the Bunsen type in which a tubular member 76 is provided with a lower flange 78 which may be attached to its associated piston by clips 79 or other suitable means and has an upper portion of conical form, as indicated at 80, which is provided with a plurality of radially extending cuts 82 extending downwardly from the peak of the cone to substantially the base thereof. The valve member is formed of a rubber material sufliciently stiff that the cuts remain closed until a substantial pressure is applied to the interior of the valve member.

The valves selected must be of such a type that, as shown in Figure 1A, when the mast tower tubes are telescoped the valves will be opened by the inlet tube 68 passing upwardly through the bores within their associated pistons. The forces involved and acting against the valves will be reviewed hereinafter.

Each of the tubes 20, 30, 40 and 50 is provided with a bore 21, 31, 41 and 51, respectively, positioned immediately above its associated piston 22, 32, 42 and 52 to provide for draining of its associated tube as will be described. As will beevident, the tube 50 is never filled with liquid during normal operation of the mast tower. The bore 51 is provided as a drain for condensate and other liquid which may accumulate in the tube.

A latch assembly, such as those indicated generally at 84 in Figure 1B, is mounted on each of the flanged sleeves 18, 28, 38 and 48. The latch assemblies each include a pair of upwardly extending arms 86 each provided with a flange 88 which is adapted to be attached to its associated sleeve 18, 28, 38 and 48, respectively, by spot welding or other suitable means. The upper ends of the arms 86 pivotally mount a latch bar 90 having its inward end provided with a suitable pad 92 of a friction material which is adapted to engage the outer wall of the inwardly adjacent tube when the latch is in a downward position as shown in Figure 2. Each latch is provided with a rod 94 pivotally mounted to the latch bar 90 and extending downwardly in such a manner as to be adapted to engage the flange of the next lower flanged sleeve. Thus, for example, the bar 94- of the latch assembly mounted on the flanged sleeve 28 is adapted to engage the flange 19 of the next lower flanged sleeve 18. The arrangement is such that when the mast is in a collapsed condition, as shown in Figures 1A and 1B, each latch is held disengaged from its associated telescoping tube by the upward thrust exerted 4 on the rod 94 by the flanged sleeve positioned therebelow.

The latch assembly affixed to the flanged ring 18 is provided with an outwardly extending portion 96 of the latch bar 90 to which is attached a downwardly extending rod 98 adapted to be engaged within a suitable keeper 99 which is attached to the ring 16 on the outermost tube 10. Inasmuch as there is no flanged sleeve below the sleeve 18. the lowermost latch assembly is not provided with a downwardly extending bar 94, and this latch assembly must be released by hand by actuation of the rod 98 as will be described.

An outlet tube 102 is connected to the bottom closure plate 12 of the mast tube 10 and is provided with a valve 104 in order to control the flow of liquid therethrough.

In operation, assuming the mast to be collapsed as shown in Figure 1, the outlet valve 104 is closed and water under pressure is supplied through the inlet tube 64 through the valve 66 and the tube 68 into the chamber below the piston 52 in the lower end of the uppermost telescopic tube 50. Pressure of the liquid acting on the base of the piston 52 will urge the uppermost mast tube 50 upwardly in its associated tube 40. The tube 50 and its skirt 54 and ring 56 will move upwardly within the tube until the ring 56 engages the flange 49 of the upper flanged sleeve 48 of the tube 40 whereupon the tube 40 will be carried upwardly by the tube 50.

As the tube 40 is carried upwardly, the flap valve 43 is carried above the end of the inlet tube 68 and then closes. from the tube 68 will act on the underside of the piston 42 and the flap valve 43 mounted thereon. In order that the tube assembly 50 and the tube assembly 40 will be raised by the pressure acting on the underside of the piston 42 and on the exposed portion of the valve 43, the total force acting on the underside of the piston 42 and the exposed portion of the valve 43 must be somewhat in excess of the weight of the tube assembly 50, the tube assembly 40 and the water contained within the tube assembly 40 below the piston 52. Furthermore, the spring action of the valve 43 must be such as to maintain this valve closed over the bore in the piston 42 against the urging of the fraction of that total force equal to the ratio of the exposed area of the valve 43 to the total area of the piston surface 42. Thus the valve closing force which may be assisted by a weight or a spring acting on the valve 43 must be greater than where A is the area of the bore 45 through the piston 42;

A is the total area of the piston 42; and

L is the weight of the telescoping tube assemblies and 40 plus the weight of the water contained within the tube 40.

The pressure acting on the underside of the piston 42 and the valve 43 will raise the tube assembly 40 in the tube 30 with the ring 46 and the downwardly extending sleeve 44 sliding upwardly in the tube 30 until the flanged sleeve 38 attached to the upper end of the tube 30 is engaged by the ring 46 of the tube assembly 40. The

- tube 30 is lifted lifting with it its associated piston 32 which, upon being raised above the end of the inlet tube 68, has its bore 35 closed by the action of its associated valve 33.

When the tube 40 reaches its uppermost position in the tube 30, the bore 41 provided in the lower portion of the tube 40 immediately above the piston 42 comes into alignment with the bore 37 in the flanged sleeve 38 and thus permits the water contained in the tube 40 to drain. It will be evident that, upon the drainage of all of the liquid contained within the tube 40, the pressure required on the underside of the piston 32 is only that which is required to raise the Weight of the tube assem- Thereafter the pressure of the liquid emerging bly 40am the tube. assembly 50.

bly 30 and the water contained therein, the tube assem- Thereafter theremaining tube assemblies are successively raised in the same fashion, i. e., when the tube eil has carried the tube 30 upwardly to the position where the valve 33 on the piston 32 is closed, the liquid pressure then acting on the underside ofthe piston 32 and its valve 33 raises the tube assemblies t 40 and 30. The tube 30 rises and, when the ring 36 engages the inwardly turned flange 2 9 of the flanged sleeve 28, the sleeve 26 islifted by the tube fxll until its valve 23 clears the inlet pipe 68 whereupon the valve 23 closes and tube 269 is raised until its associated ring26 engages the inwardly permost latch assembly 84 which is mounted on the flanged sleeve 43 will prevent the tube 53' from moving downwardly more than a limited degree by becoming wedged against the outer wall of the tube 4t? between the tube and the bracket 86. Similarly, when the sleeve 30 reaches itsupperrnost position and the liquid contained therein commences to drain through its outlet bore 31 and the associated bore 27, the latch bar mounted on the flange ring 38 will engage the tube 46) and prevent it from moving downwardly more than the distance necessary to engage the latch bar. This automatic latching takes place with each successive tube assembly after it has reached its uppermost position and the tube below it is being drained of the liquid contained therein. When the entire mast has been extended, the valve as may be closed off preventing the delivery of further liquid into the mast tower and the valve 1% may then be opened to provide for draining of the lowermost tube 1% of the tower. Thus when the entire mast tower is completely extended, it is drained of all water and thus damage due to freezing or corrosion or otherwise occurring due to the existence of the water within the tube over extended periods of time is avoided.

When it is desired to collapse the mast tower, the lowermost latch assembly 84 may be released by actuation of the rod 98. Release of the lowermost latch assembly permits the tube 2t) to move downwardly within the tube to its lowermost position as indicated in Figure 1. It will be evident that, as the tube 26 moves downwardly, the tubes 3d, 40 and 50 which are held in rigid relative positions by their associated latch assemblies 84 will move downwardly therewith. In order to provide a cushioning for the descending tube 20, the drain valve 194 is maintained in a closed position. The air compressed below the piston 22 may escape past the valve 23, through the minute spaces existing between the tube 10 and the flange 24 or, alternately, may be bled out slowly through the drain valve 164 by manual manipulation thereof. Additional cushioning may be provided by the admission of a quantity of water into the tube 10 prior to the release of the lowermost latch 84.

In order to permit complete collapse of the tube 24 within the tube 141 to the position indicated in Figure 1A, it is necessary that the valve 23 be opened upon its engagement with the upper end of the inlet pipe 68. In order to open in this fashion, the valve closing force must be less than the total weight of the tube assemblies extending thereabove. It will be evident that the force represented by this total weight will be greater than the force which the valve must necessarily resist to provide for extension of the mast tower as hereinbefore set forth. Thus the valve closing force must be selected to be intermediate of these two forces in order to provide an operable mast assembly.

immediately prior to the seating of the skirt 24 on the closure plate 12 the downwardly extending rod 94 of the latch assembly mounted on the flanged-sleeve 28 will engage the inwardly turned flange 19 of the flanged sleeve 13 and will raise the latch bar releasing it from the next inner tube 30. The tube 30 will then move downwardly within the tube 2%. When the tube assembly 30 has arrived at its lowermost position, the latch assembly mounted thereon is released by engagement of its rod 94 with the flange 29 of the flange sleeve 28 and thus the successive mast tubes move downwardly into the telescoped condition such as shown in Figure 1.

The collapse of each of the successive mast tubes may be cushioned in a manner similar to the cushioning of the collapse of the mast tube 20 and, when the mast tubes are all completely collapsed, they will assume positions as shown in Figure 1A in which the lower edge of the skirt of each of the tubes will be at rest upon the upper surface of the piston of the next lower tube.

After the mast is completely collapsed, all liquid may be drained therefrom through the outlet valve me.

If it is desired to provide a more positive seal between the skirt of each of the telescoping tubes and the next outer tube with which the skirts are in slidable engagement, an arrangement may be provided, such as is shown in Figure 5, in which a tube is provided with a skirt 124 which is adapted to slide within a tube 110. The tube 12% is provided with a lowermost piston member 122 identical to that described in connection with the various tubes shown in Figures 12. The skirt 124 in this modification is, however, provided with a channel formed portion 126 within which there is seated an Q- ring or other suitable sealing means 128. This construction, it will be evident, provides a substantially completely liquid-tight seal between the skirt 124 and the tube 116 within which the skirt slides.

While the invention disclosed herein has been described as embodied in a collapsible and expansible mast tower of a type adapted to support, for example, a television antenna, it will be evident that the expansible tower as described and claimed may be employed in a variety of ap plications. While for convenience the actuating liquid has been referred to above as water, it will be evident that any suitable hydraulic actuating fluid may be employed. The essential aspects of the invention are the provision of a tower which is urged upwardly by a liquid pressure and in which it is not necessary that the column of liquid be raised the total height of the tower.

Additionally, there is provided a tower which may be extended merely by the manipulation of a single hydraulic fluid control valve and is readily collapsible by the manipulation of a single latch release bar and a valve or valves to provide cushioning for the successively collapsing tubes upon their collapse. In addition to these operational aspects, it is noted that the mast tower may be retained in either a completely extended condition or a completely collapsed condition without necessity of retaining any liquid within the mast tower.

What is claimed is:

1. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing off the lower ends of each of said tubes, means for successively applying fluid pressure to the undersides of said closing means for moving said tubes successively from a collapsed relation to an extended relation starting with the innermost closing means and tube, and means for limiting the degree of extension of each of said tubes.

2. A telescoping mast comprising means providing a lurality of mast tubes in telescoping relation, means for closing off the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, means for limiting the degree of extension of said tubes, means for retaining each of said tubes in extended position, and means for .7 v draining the fluid from each of said tubes when it is in its fully extended position.

3. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing oif the lower ends of each of said tubes, means for successively applying fluid pressure to the undersides of said closing means for moving said tubes successively from a collapsed relation to an extended relation, the innermost closing means being the first to receive pressure and the innermost tube being the first to be extended, means for limiting the degree of extension of each of said tubes, means for retaining each of said tubes in an extended position, and means for draining the fluid from each of said tubes when it is in its fully extended position.

4. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing oi? the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means, said closing means including valve means adapted to close off the bores in said closing means when each closing means is above the upper end i.

of said pipe, and means for limiting the degree of extension of said tubes.

5. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing ofi the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means and terminating below the closing means of the innermost tube, said closing means including valve means adapted to close off the bores in said closing means when each closing means is above the upper end of said pipe, and means for limiting the degree of extension of said tubes.

6. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing off the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means, said closing means including valve means adapted to close off the bores in said closing means when each closing means is above the upper end of said pipe, means for limiting the degree of extension of said tubes, means for retaining each of said tubes in an extended position, and means for draining the fluid from each of said tubes when it is in its fully extended position.

7. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing off the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means, said closing means including valve means adapted to close oil the bores in said closing means when each closing means is above the upper end of said pipe, means for retaining each of said tubes in an extended position, means for draining the fluid from each of said tubes when it is in its fully extended position, and means for releasing said retaining means to permit the tubes to move from an extended relation to a collapsed relation, said valve means being opened by the inlet pipe when the closing means move downwardly thereover when the mast is collapsed.

8. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing 0E the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving, said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means, said closing means including valve means adapted to close ofl the bores in said closing means when each closing means is above the upper end of said pipe, means for retaining each of said tubes in an extended position, means for draining the fluid from each of said tubes when it is in its fully extended position, and means for releasing said retaining means to permit the tubes to move from an extended relation to a collapsed relation, said valve means being of flap type adapted to be opened by the inlet pipe when the closing means move downwardly thereover when the mast is collapsed.

9. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing ofl the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, said fluid pressure applying means including a pipe extending upwardly through bores in said closing means, said closing means including valve means adapted to close olf the bores in said closing means when each closing means is 4 above the upper end of said pipe, means for retaining each of said tubes in an extended position, means for draining the fluid from each of said tubes when it is in its fully extended position, and means for releasing said retaining means to permit the tubes to move from an extended relation to a collapsed relation, said valve means being of Bunsen type adapted to be opened by the inlet pipe when the closing means move downwardly thereover when the mast is collapsed.

10. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for closing off the lower ends of each of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, means for limiting the degree of extension of said tubes, latching means for retaining each of said tubes in an extended position, manually operated means for first releasing the latching means for the lowermost extended tube, and means responsive to the telescoping of each of said tubes for releasing the latching means of the next successive tube.

11. A telescoping mast comprising a plurality of mast tubes in spaced telescoping relation, means for closing ofl the lower ends of each of said tubes, skirts attached to the exterior of the lower ends of the tubes and extending downwardly therefrom, the upper end of each of said skirts terminating adjacent to the closing means of its associated tube, each skirt being in slidable sealing engagement with the inside wall of the next outer tube, members attached to the exteriors of the tubes above the skirts, each of said tubes having a drain opening between its associated skirt and member, means at the upper ends of the tubes for engaging the members of the next inner tubes to limit the degree of extension of said tubes, means for applying fluid pressure to the underside of each of said closing means for moving said tubes from a collapsed relation to an extended relation, means for latching each of said tubes in an extended position and means for releasing said latching means.

12. A telescoping mast comprising means providing a plurality of mast tubes in telescoping relation, means for moving said tubes from a collapsed relation to an extended relation, means for limiting the degree of extension of said tubes, latching means for retaining each of said tubesin an extended position, manually operated means for first releasing the latching means for the lowermost extended tube, and means responsive to the telescoping of each of said tubes for releasing the latching means of the next successive tube.

References Cited in the file of this patent UNITED STATES PATENTS 165,472 Brinckerhoff July 13, 1875 332,418 Morey Dec. 15, 1885 902,723

Gauer Nov. 3, 1908 

